My buddy Steve has a Go camera. It's been dropped, run over, submerged and hit whilest cycling, skiing and kayaking. He mounts either on top of his helmet or in a chest harness. It's a durable little sucker. Video quality seems good to me. Chest-mounted, it works well, on top of your brain bucket it's pretty tall compared to the bullet form factor IMHO. But no overhanging rocks or trees have broken it, a couple enough to knock him off the bike.
"Stand your ground. Don't fire unless fired upon, but if they mean to have a war, let it begin here." -- Capt. John Parker